The present invention generally relates to reel base drive apparatus, and more particularly to an apparatus for driving reel bases of a tape recorder.
It is desirable that a reel base drive apparatus be constructed to have no torque fluctuation of a reel motor influencing the motions of reel bases to minimize wow and flutter of the tape recorder, that the reel base drive apparatus require only a small number of parts in view of the cost of manufacturing products, and that the apparatus have high reliability.
Japanese laid-open utility model publication no. 60-44237 proposes the use of a torsion coil spring in a rotation transmitting system of a reel shaft drive apparatus which connects a reel motor to reel shafts for absorbing torque fluctuation of the reel motor. Elastic deformation of the torsion coil spring serves to absorb the torque fluctuation of the reel motor in operation.
A reel driving apparatus of the type similar to the above-described conventional apparatus requires a mechanism for serving to sway an arm through rotation of a reel motor. For this purpose, such a mechanism has a felt member provided between an arm and an idler to generate a frictional force for obtaining an oscillatory motion of the arm for smaller torque change.
However, for using such a felt member, a greater number of parts are necessary than that of the apparatus having no felt member, and the occurrence of a frictional force causes a loss of torque generated by the reel motor.
Further, changed properties of the felt member after long time use cause a change in the frictional force from the initial level, and a varying oscillatory force is applied to the arm, resulting in unstable driving of the reel shafts of the tape recorder.